Question

Select all angle measures for which sin(∅) = - ( (√2) /2)

Answer 1

Answer:

b) 5π/4

c) 7π/4

e) 13π/4

Step-by-step explanation:

sin θ = -½√2

There's really no algebra to be done here.  There are two ways you can solve.  One, you can use a calculator.  Two, you can memorize your unit circle.

Either way, it helps to draw the unit circle.  sin θ is the y coordinate, so you're looking for points on the circle where y = -½√2.  This happens at two places: θ = 5π/4 and 7π/4.

Next, we need to check the options that are greater than 2π.

9π/4 is the same as π/4.

13π/4 is the same as 5π/4.

So the three correct answers are 5π/4, 7π/4, and 13π/4.